Most likely Israel would be busy invading Lebanon and Syria, and the US will have the 'help' of Saudi etc instead unless they get them to go draw an F15 in the corner while the adults are working. Six months later we'll get "who would have thought international relations were this complicated?"
It certainly doesn't help that the only time the US media as a whole ever gets behind Trump is when he's firing missiles at people. The preference for stupid 'strength' over nuanced sense isn't just from Trump.
Israel trying both would be a disaster, I would wager, as well. Heck even one.
Israel would 'win' even against both, but very much with the air quotes. Their main aim would almost certainly be to restart/ exacerbate the civil wars there to get their enemies fighting each other rather than doing prolonged fighting themselves. They might achieve it, but it seems unlikely since the single unifying strand in Syria and Lebanon is hatred of Israel, so anyone helping them will be viewed as a traitor. Plus there's the question of what Russia would do under such circumstances, and while Putin seems OK with some limited strikes by Israel he's temperamentally unlikely to back down if Israel tries more than that.
Fundamentally though, any invasion of Iran will result in their proxies fighting whatever 'coalition' is scraped together throughout Lebanon to Iran, and that practically means that Iraq, Syria and Lebanon become involved whatever anyone wants; and that will involve Israel either invading pre-emptively or being dragged in.
Fair enough, was thinking their aim would be something more than setting fire to the neighbour's houses. I had thought the aim would be to crush Hezbollah, which I doubt they can do without getting stuck in one messy and expensive conflict their public would tire of. Maybe I'm underestimating the IDF, though. Good thing I am not a head of a foreign office